[{"page":"142","ddc":["530"],"doi":"10.15479/at:ista:14622","article_processing_charge":"No","alternative_title":["ISTA Thesis"],"publisher":"Institute of Science and Technology Austria","date_updated":"2023-12-13T14:47:25Z","_id":"14622","type":"dissertation","degree_awarded":"PhD","project":[{"_id":"bd660c93-d553-11ed-ba76-fb0fb6f49c0d","name":"Quantum_Quantum Circuits and Software_Variational quantum algorithms on NISQ devices"},{"_id":"23841C26-32DE-11EA-91FC-C7463DDC885E","name":"Non-Ergodic Quantum Matter: Universality, Dynamics and Control","grant_number":"850899","call_identifier":"H2020"}],"status":"public","ec_funded":1,"date_published":"2023-11-30T00:00:00Z","year":"2023","related_material":{"record":[{"id":"11471","status":"public","relation":"part_of_dissertation"},{"id":"13125","status":"public","relation":"part_of_dissertation"},{"status":"public","relation":"part_of_dissertation","id":"9760"}]},"has_accepted_license":"1","tmp":{"image":"/images/cc_by_nc_sa.png","name":"Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)","legal_code_url":"https://creativecommons.org/licenses/by-nc-sa/4.0/legalcode","short":"CC BY-NC-SA (4.0)"},"publication_identifier":{"issn":["2663 - 337X"]},"publication_status":"published","file_date_updated":"2023-12-01T11:10:46Z","author":[{"id":"dd622248-f6e0-11ea-865d-ce382a1c81a5","full_name":"Sack, Stefan","last_name":"Sack","first_name":"Stefan","orcid":"0000-0001-5400-8508"}],"day":"30","title":"Improving variational quantum algorithms: Innovative initialization techniques and extensions to qudit systems","oa_version":"Published Version","date_created":"2023-11-28T10:58:13Z","language":[{"iso":"eng"}],"citation":{"apa":"Sack, S. (2023). <i>Improving variational quantum algorithms: Innovative initialization techniques and extensions to qudit systems</i>. Institute of Science and Technology Austria. <a href=\"https://doi.org/10.15479/at:ista:14622\">https://doi.org/10.15479/at:ista:14622</a>","mla":"Sack, Stefan. <i>Improving Variational Quantum Algorithms: Innovative Initialization Techniques and Extensions to Qudit Systems</i>. Institute of Science and Technology Austria, 2023, doi:<a href=\"https://doi.org/10.15479/at:ista:14622\">10.15479/at:ista:14622</a>.","ista":"Sack S. 2023. Improving variational quantum algorithms: Innovative initialization techniques and extensions to qudit systems. Institute of Science and Technology Austria.","chicago":"Sack, Stefan. “Improving Variational Quantum Algorithms: Innovative Initialization Techniques and Extensions to Qudit Systems.” Institute of Science and Technology Austria, 2023. <a href=\"https://doi.org/10.15479/at:ista:14622\">https://doi.org/10.15479/at:ista:14622</a>.","ieee":"S. Sack, “Improving variational quantum algorithms: Innovative initialization techniques and extensions to qudit systems,” Institute of Science and Technology Austria, 2023.","short":"S. Sack, Improving Variational Quantum Algorithms: Innovative Initialization Techniques and Extensions to Qudit Systems, Institute of Science and Technology Austria, 2023.","ama":"Sack S. Improving variational quantum algorithms: Innovative initialization techniques and extensions to qudit systems. 2023. doi:<a href=\"https://doi.org/10.15479/at:ista:14622\">10.15479/at:ista:14622</a>"},"user_id":"8b945eb4-e2f2-11eb-945a-df72226e66a9","supervisor":[{"first_name":"Maksym","orcid":"0000-0002-2399-5827","last_name":"Serbyn","id":"47809E7E-F248-11E8-B48F-1D18A9856A87","full_name":"Serbyn, Maksym"}],"month":"11","department":[{"_id":"GradSch"},{"_id":"MaSe"}],"file":[{"checksum":"068fd3570506ec42b2faa390de784bc4","relation":"main_file","content_type":"application/pdf","access_level":"closed","file_name":"PhD_Thesis.pdf","embargo_to":"open_access","file_id":"14635","embargo":"2024-11-30","creator":"ssack","date_updated":"2023-12-01T11:10:46Z","date_created":"2023-11-30T15:53:10Z","file_size":11947523},{"access_level":"closed","content_type":"application/zip","file_name":"PhD Thesis (1).zip","checksum":"0fa3bc0d108aed0ac59d2c6beef2220a","relation":"source_file","date_updated":"2023-12-01T11:10:46Z","creator":"ssack","file_size":18422964,"date_created":"2023-11-30T15:54:11Z","file_id":"14636"}]},{"citation":{"ama":"Sack S, Medina Ramos RA, Kueng R, Serbyn M. Recursive greedy initialization of the quantum approximate optimization algorithm with guaranteed improvement. <i>Physical Review A</i>. 2023;107(6). doi:<a href=\"https://doi.org/10.1103/physreva.107.062404\">10.1103/physreva.107.062404</a>","ieee":"S. Sack, R. A. Medina Ramos, R. Kueng, and M. Serbyn, “Recursive greedy initialization of the quantum approximate optimization algorithm with guaranteed improvement,” <i>Physical Review A</i>, vol. 107, no. 6. American Physical Society, 2023.","short":"S. Sack, R.A. Medina Ramos, R. Kueng, M. Serbyn, Physical Review A 107 (2023).","chicago":"Sack, Stefan, Raimel A Medina Ramos, Richard Kueng, and Maksym Serbyn. “Recursive Greedy Initialization of the Quantum Approximate Optimization Algorithm with Guaranteed Improvement.” <i>Physical Review A</i>. American Physical Society, 2023. <a href=\"https://doi.org/10.1103/physreva.107.062404\">https://doi.org/10.1103/physreva.107.062404</a>.","ista":"Sack S, Medina Ramos RA, Kueng R, Serbyn M. 2023. Recursive greedy initialization of the quantum approximate optimization algorithm with guaranteed improvement. Physical Review A. 107(6), 062404.","apa":"Sack, S., Medina Ramos, R. A., Kueng, R., &#38; Serbyn, M. (2023). Recursive greedy initialization of the quantum approximate optimization algorithm with guaranteed improvement. <i>Physical Review A</i>. American Physical Society. <a href=\"https://doi.org/10.1103/physreva.107.062404\">https://doi.org/10.1103/physreva.107.062404</a>","mla":"Sack, Stefan, et al. “Recursive Greedy Initialization of the Quantum Approximate Optimization Algorithm with Guaranteed Improvement.” <i>Physical Review A</i>, vol. 107, no. 6, 062404, American Physical Society, 2023, doi:<a href=\"https://doi.org/10.1103/physreva.107.062404\">10.1103/physreva.107.062404</a>."},"issue":"6","user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","oa":1,"language":[{"iso":"eng"}],"department":[{"_id":"MaSe"}],"file":[{"content_type":"application/pdf","access_level":"open_access","file_name":"2023_PhysRevA_Sack.pdf","success":1,"checksum":"0d71423888eeccaa60d8f41197f26306","relation":"main_file","creator":"dernst","date_updated":"2023-06-13T07:28:36Z","file_size":2524611,"date_created":"2023-06-13T07:28:36Z","file_id":"13131"}],"article_number":"062404","arxiv":1,"month":"06","file_date_updated":"2023-06-13T07:28:36Z","publication_status":"published","publication_identifier":{"eissn":["2469-9934"],"issn":["2469-9926"]},"has_accepted_license":"1","abstract":[{"text":"The quantum approximate optimization algorithm (QAOA) is a variational quantum algorithm, where a quantum computer implements a variational ansatz consisting of p layers of alternating unitary operators and a classical computer is used to optimize the variational parameters. For a random initialization, the optimization typically leads to local minima with poor performance, motivating the search for initialization strategies of QAOA variational parameters. Although numerous heuristic initializations exist, an analytical understanding and performance guarantees for large p remain evasive.We introduce a greedy initialization of QAOA which guarantees improving performance with an increasing number of layers. Our main result is an analytic construction of 2p + 1 transition states—saddle points with a unique negative curvature direction—for QAOA with p + 1 layers that use the local minimum of QAOA with p layers. Transition states connect to new local minima, which are guaranteed to lower the energy compared to the minimum found for p layers. We use the GREEDY procedure to navigate the exponentially increasing with p number of local minima resulting from the recursive application of our analytic construction. The performance of the GREEDY procedure matches available initialization strategies while providing a guarantee for the minimal energy to decrease with an increasing number of layers p. ","lang":"eng"}],"tmp":{"name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","short":"CC BY (4.0)"},"intvolume":"       107","volume":107,"date_created":"2023-06-07T06:57:32Z","article_type":"original","scopus_import":"1","day":"02","author":[{"id":"dd622248-f6e0-11ea-865d-ce382a1c81a5","full_name":"Sack, Stefan","last_name":"Sack","first_name":"Stefan","orcid":"0000-0001-5400-8508"},{"orcid":"0000-0002-5383-2869","first_name":"Raimel A","full_name":"Medina Ramos, Raimel A","id":"CE680B90-D85A-11E9-B684-C920E6697425","last_name":"Medina Ramos"},{"first_name":"Richard","full_name":"Kueng, Richard","last_name":"Kueng"},{"first_name":"Maksym","orcid":"0000-0002-2399-5827","last_name":"Serbyn","full_name":"Serbyn, Maksym","id":"47809E7E-F248-11E8-B48F-1D18A9856A87"}],"oa_version":"Published Version","title":"Recursive greedy initialization of the quantum approximate optimization algorithm with guaranteed improvement","ec_funded":1,"date_published":"2023-06-02T00:00:00Z","acknowledgement":"We thank V. Verteletskyi for a joint collaboration on numerical studies of the QAOA during his internship at ISTA that inspired analytic results on TS reported in this work. We acknowledge A. A. Mele and M. Brooks for discussions and D. Egger, P. Love, and D. Wierichs for valuable feedback on the manuscript. S.H.S., R.A.M., and M.S. acknowledge support by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (Grant Agreement No. 850899). R.K. is supported by the SFB BeyondC (Grant No. F7107-N38) and the project QuantumReady (FFG 896217). ","status":"public","publication":"Physical Review A","project":[{"_id":"23841C26-32DE-11EA-91FC-C7463DDC885E","grant_number":"850899","name":"Non-Ergodic Quantum Matter: Universality, Dynamics and Control","call_identifier":"H2020"}],"year":"2023","isi":1,"related_material":{"record":[{"status":"public","relation":"dissertation_contains","id":"14622"}]},"external_id":{"arxiv":["2209.01159"],"isi":["001016927100012"]},"quality_controlled":"1","ddc":["530"],"_id":"13125","date_updated":"2023-12-13T14:47:25Z","type":"journal_article","article_processing_charge":"No","doi":"10.1103/physreva.107.062404","publisher":"American Physical Society"},{"status":"public","publication":"PRX Quantum","project":[{"call_identifier":"H2020","name":"Non-Ergodic Quantum Matter: Universality, Dynamics and Control","grant_number":"850899","_id":"23841C26-32DE-11EA-91FC-C7463DDC885E"}],"date_published":"2022-06-29T00:00:00Z","acknowledgement":"We thank Marco Cerezo, Zoe Holmes, and Nicholas Hunter-Jones for fruitful discussion and valuable feedback. We also acknowledge Adam Smith, Johannes Jakob Meyer, and Victor V. Albert for comments on the paper. The simulations were performed in the Julia programming\r\nlanguage [65] using the Yao module [66]. S.H.S., R.A.M., A.A.M. and M.S. acknowledge support by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (Grant Agreement No. 850899).","ec_funded":1,"related_material":{"record":[{"status":"public","relation":"dissertation_contains","id":"14622"}]},"external_id":{"arxiv":["2201.08194"],"isi":["000822564300001"]},"year":"2022","isi":1,"keyword":["General Medicine"],"ddc":["530"],"quality_controlled":"1","publisher":"American Physical Society","article_processing_charge":"No","doi":"10.1103/prxquantum.3.020365","type":"journal_article","_id":"11471","date_updated":"2023-12-13T14:47:24Z","language":[{"iso":"eng"}],"oa":1,"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","citation":{"mla":"Sack, Stefan, et al. “Avoiding Barren Plateaus Using Classical Shadows.” <i>PRX Quantum</i>, vol. 3, no. 2, 020365, American Physical Society, 2022, doi:<a href=\"https://doi.org/10.1103/prxquantum.3.020365\">10.1103/prxquantum.3.020365</a>.","apa":"Sack, S., Medina Ramos, R. A., Michailidis, A., Kueng, R., &#38; Serbyn, M. (2022). Avoiding barren plateaus using classical shadows. <i>PRX Quantum</i>. American Physical Society. <a href=\"https://doi.org/10.1103/prxquantum.3.020365\">https://doi.org/10.1103/prxquantum.3.020365</a>","chicago":"Sack, Stefan, Raimel A Medina Ramos, Alexios Michailidis, Richard Kueng, and Maksym Serbyn. “Avoiding Barren Plateaus Using Classical Shadows.” <i>PRX Quantum</i>. American Physical Society, 2022. <a href=\"https://doi.org/10.1103/prxquantum.3.020365\">https://doi.org/10.1103/prxquantum.3.020365</a>.","ista":"Sack S, Medina Ramos RA, Michailidis A, Kueng R, Serbyn M. 2022. Avoiding barren plateaus using classical shadows. PRX Quantum. 3(2), 020365.","short":"S. Sack, R.A. Medina Ramos, A. Michailidis, R. Kueng, M. Serbyn, PRX Quantum 3 (2022).","ieee":"S. Sack, R. A. Medina Ramos, A. Michailidis, R. Kueng, and M. Serbyn, “Avoiding barren plateaus using classical shadows,” <i>PRX Quantum</i>, vol. 3, no. 2. American Physical Society, 2022.","ama":"Sack S, Medina Ramos RA, Michailidis A, Kueng R, Serbyn M. Avoiding barren plateaus using classical shadows. <i>PRX Quantum</i>. 2022;3(2). doi:<a href=\"https://doi.org/10.1103/prxquantum.3.020365\">10.1103/prxquantum.3.020365</a>"},"issue":"2","month":"06","arxiv":1,"article_number":"020365","file":[{"content_type":"application/pdf","access_level":"open_access","file_name":"2022_PRXQuantum_Sack.pdf","success":1,"checksum":"a7706b28d24a0e32a55ea04b82a2df43","relation":"main_file","date_updated":"2022-06-30T07:14:48Z","creator":"dernst","date_created":"2022-06-30T07:14:48Z","file_size":4231591,"file_id":"11472"}],"department":[{"_id":"MaSe"}],"abstract":[{"text":"Variational quantum algorithms are promising algorithms for achieving quantum advantage on nearterm devices. The quantum hardware is used to implement a variational wave function and measure observables, whereas the classical computer is used to store and update the variational parameters. The optimization landscape of expressive variational ansätze is however dominated by large regions in parameter space, known as barren plateaus, with vanishing gradients, which prevents efficient optimization. In this work we propose a general algorithm to avoid barren plateaus in the initialization and throughout the optimization. To this end we define a notion of weak barren plateaus (WBPs) based on the entropies of local reduced density matrices. The presence of WBPs can be efficiently quantified using recently introduced shadow tomography of the quantum state with a classical computer. We demonstrate that avoidance of WBPs suffices to ensure sizable gradients in the initialization. In addition, we demonstrate that decreasing the gradient step size, guided by the entropies allows WBPs to be avoided during the optimization process. This paves the way for efficient barren plateau-free optimization on near-term devices. ","lang":"eng"}],"tmp":{"name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","short":"CC BY (4.0)"},"intvolume":"         3","has_accepted_license":"1","file_date_updated":"2022-06-30T07:14:48Z","publication_status":"published","publication_identifier":{"issn":["2691-3399"]},"title":"Avoiding barren plateaus using classical shadows","oa_version":"Published Version","day":"29","author":[{"id":"dd622248-f6e0-11ea-865d-ce382a1c81a5","full_name":"Sack, Stefan","last_name":"Sack","first_name":"Stefan","orcid":"0000-0001-5400-8508"},{"id":"CE680B90-D85A-11E9-B684-C920E6697425","full_name":"Medina Ramos, Raimel A","last_name":"Medina Ramos","orcid":"0000-0002-5383-2869","first_name":"Raimel A"},{"first_name":"Alexios","orcid":"0000-0002-8443-1064","full_name":"Michailidis, Alexios","id":"36EBAD38-F248-11E8-B48F-1D18A9856A87","last_name":"Michailidis"},{"last_name":"Kueng","full_name":"Kueng, Richard","first_name":"Richard"},{"id":"47809E7E-F248-11E8-B48F-1D18A9856A87","full_name":"Serbyn, Maksym","last_name":"Serbyn","orcid":"0000-0002-2399-5827","first_name":"Maksym"}],"date_created":"2022-06-29T20:21:32Z","article_type":"original","volume":3},{"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","issue":"4","citation":{"mla":"Stocker, Lidia, et al. “Entanglement-Based Observables for Quantum Impurities.” <i>Physical Review Research</i>, vol. 4, no. 4, 043177, American Physical Society, 2022, doi:<a href=\"https://doi.org/10.1103/PhysRevResearch.4.043177\">10.1103/PhysRevResearch.4.043177</a>.","apa":"Stocker, L., Sack, S., Ferguson, M. S., &#38; Zilberberg, O. (2022). Entanglement-based observables for quantum impurities. <i>Physical Review Research</i>. American Physical Society. <a href=\"https://doi.org/10.1103/PhysRevResearch.4.043177\">https://doi.org/10.1103/PhysRevResearch.4.043177</a>","chicago":"Stocker, Lidia, Stefan Sack, Michael S. Ferguson, and Oded Zilberberg. “Entanglement-Based Observables for Quantum Impurities.” <i>Physical Review Research</i>. American Physical Society, 2022. <a href=\"https://doi.org/10.1103/PhysRevResearch.4.043177\">https://doi.org/10.1103/PhysRevResearch.4.043177</a>.","ista":"Stocker L, Sack S, Ferguson MS, Zilberberg O. 2022. Entanglement-based observables for quantum impurities. Physical Review Research. 4(4), 043177.","short":"L. Stocker, S. Sack, M.S. Ferguson, O. Zilberberg, Physical Review Research 4 (2022).","ieee":"L. Stocker, S. Sack, M. S. Ferguson, and O. Zilberberg, “Entanglement-based observables for quantum impurities,” <i>Physical Review Research</i>, vol. 4, no. 4. American Physical Society, 2022.","ama":"Stocker L, Sack S, Ferguson MS, Zilberberg O. Entanglement-based observables for quantum impurities. <i>Physical Review Research</i>. 2022;4(4). doi:<a href=\"https://doi.org/10.1103/PhysRevResearch.4.043177\">10.1103/PhysRevResearch.4.043177</a>"},"language":[{"iso":"eng"}],"oa":1,"article_number":"043177","file":[{"date_created":"2023-01-20T12:03:31Z","file_size":2941167,"date_updated":"2023-01-20T12:03:31Z","creator":"dernst","file_id":"12328","success":1,"file_name":"2022_PhysicalReviewResearch_Stocker.pdf","access_level":"open_access","content_type":"application/pdf","relation":"main_file","checksum":"556820cf6e4af77c8476e5b8f4114d1a"}],"department":[{"_id":"MaSe"}],"month":"12","publication_status":"published","publication_identifier":{"issn":["2643-1564"]},"file_date_updated":"2023-01-20T12:03:31Z","abstract":[{"lang":"eng","text":"Quantum impurities exhibit fascinating many-body phenomena when the small interacting impurity changes the physics of a large noninteracting environment. The characterisation of such strongly correlated nonperturbative effects is particularly challenging due to the infinite size of the environment, and the inability of local correlators to capture the buildup of long-ranged entanglement in the system. Here, we harness an entanglement-based observable—the purity of the impurity—as a witness for the formation of strong correlations. We showcase the utility of our scheme by exactly solving the open Kondo box model in the small box limit, and thus describe all-electronic dot-cavity devices. Specifically, we conclusively characterize the metal-to-insulator phase transition in the system and identify how the (conducting) dot-lead Kondo singlet is quenched by an (insulating) intraimpurity singlet formation. Furthermore, we propose an experimentally feasible tomography protocol for the measurement of the purity, which motivates the observation of impurity physics through their entanglement build up."}],"tmp":{"name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","short":"CC BY (4.0)"},"intvolume":"         4","has_accepted_license":"1","article_type":"original","date_created":"2023-01-08T23:00:53Z","volume":4,"oa_version":"Published Version","title":"Entanglement-based observables for quantum impurities","author":[{"full_name":"Stocker, Lidia","last_name":"Stocker","first_name":"Lidia"},{"first_name":"Stefan","last_name":"Sack","full_name":"Sack, Stefan","id":"dd622248-f6e0-11ea-865d-ce382a1c81a5"},{"first_name":"Michael S.","last_name":"Ferguson","full_name":"Ferguson, Michael S."},{"first_name":"Oded","last_name":"Zilberberg","full_name":"Zilberberg, Oded"}],"day":"01","scopus_import":"1","acknowledgement":"We thank G. Blatter, T. Ihn, K. Ensslin, M. Goldstein, C. Carisch, and J. del Pino for illuminating discussions and acknowledge financial support from the Swiss National Science Foundation (SNSF) through Project No. 190078, and from the Deutsche Forschungsgemeinschaft (DFG) - Project No. 449653034. Our numerical implementations are based on the ITensors JULIA library [64].","date_published":"2022-12-01T00:00:00Z","publication":"Physical Review Research","status":"public","year":"2022","quality_controlled":"1","ddc":["530"],"type":"journal_article","date_updated":"2023-02-13T09:08:28Z","_id":"12111","publisher":"American Physical Society","doi":"10.1103/PhysRevResearch.4.043177","article_processing_charge":"No"},{"ddc":["530"],"quality_controlled":"1","doi":"10.22331/Q-2021-07-01-491","article_processing_charge":"Yes","publisher":"Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften","date_updated":"2023-12-13T14:47:25Z","_id":"9760","type":"journal_article","project":[{"_id":"23841C26-32DE-11EA-91FC-C7463DDC885E","call_identifier":"H2020","grant_number":"850899","name":"Non-Ergodic Quantum Matter: Universality, Dynamics and Control"}],"status":"public","publication":"Quantum","ec_funded":1,"acknowledgement":"We would like to thank D. Abanin and R. Medina for fruitful discussions and A. Smith and I. Kim for valuable feedback on the manuscript. We acknowledge support by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (Grant Agreement No. 850899).","date_published":"2021-07-01T00:00:00Z","isi":1,"year":"2021","external_id":{"arxiv":["2101.05742"],"isi":["000669830600001"]},"related_material":{"record":[{"id":"14622","status":"public","relation":"dissertation_contains"}]},"has_accepted_license":"1","intvolume":"         5","tmp":{"name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","short":"CC BY (4.0)"},"abstract":[{"text":"The quantum approximate optimization algorithm (QAOA) is a prospective near-term quantum algorithm due to its modest circuit depth and promising benchmarks. However, an external parameter optimization required in the QAOA could become a performance bottleneck. This motivates studies of the optimization landscape and search for heuristic ways of parameter initialization. In this work we visualize the optimization landscape of the QAOA applied to the MaxCut problem on random graphs, demonstrating that random initialization of the QAOA is prone to converging to local minima with suboptimal performance. We introduce the initialization of QAOA parameters based on the Trotterized quantum annealing (TQA) protocol, parameterized by the Trotter time step. We find that the TQA initialization allows to circumvent\r\nthe issue of false minima for a broad range of time steps, yielding the same performance as the best result out of an exponentially scaling number of random initializations. Moreover, we demonstrate that the optimal value of the time step coincides with the point of proliferation of Trotter errors in quantum annealing. Our results suggest practical ways of initializing QAOA protocols on near-term quantum devices and reveal new connections between QAOA and quantum annealing.","lang":"eng"}],"publication_status":"published","publication_identifier":{"eissn":["2521-327X"]},"file_date_updated":"2021-08-06T06:44:31Z","author":[{"last_name":"Sack","full_name":"Sack, Stefan","id":"dd622248-f6e0-11ea-865d-ce382a1c81a5","first_name":"Stefan","orcid":"0000-0001-5400-8508"},{"full_name":"Serbyn, Maksym","id":"47809E7E-F248-11E8-B48F-1D18A9856A87","last_name":"Serbyn","orcid":"0000-0002-2399-5827","first_name":"Maksym"}],"day":"01","scopus_import":"1","oa_version":"Published Version","title":"Quantum annealing initialization of the quantum approximate optimization algorithm","volume":5,"article_type":"original","date_created":"2021-08-01T22:01:21Z","oa":1,"language":[{"iso":"eng"}],"citation":{"ista":"Sack S, Serbyn M. 2021. Quantum annealing initialization of the quantum approximate optimization algorithm. Quantum. 5, 491.","chicago":"Sack, Stefan, and Maksym Serbyn. “Quantum Annealing Initialization of the Quantum Approximate Optimization Algorithm.” <i>Quantum</i>. Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften, 2021. <a href=\"https://doi.org/10.22331/Q-2021-07-01-491\">https://doi.org/10.22331/Q-2021-07-01-491</a>.","mla":"Sack, Stefan, and Maksym Serbyn. “Quantum Annealing Initialization of the Quantum Approximate Optimization Algorithm.” <i>Quantum</i>, vol. 5, 491, Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften, 2021, doi:<a href=\"https://doi.org/10.22331/Q-2021-07-01-491\">10.22331/Q-2021-07-01-491</a>.","apa":"Sack, S., &#38; Serbyn, M. (2021). Quantum annealing initialization of the quantum approximate optimization algorithm. <i>Quantum</i>. Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften. <a href=\"https://doi.org/10.22331/Q-2021-07-01-491\">https://doi.org/10.22331/Q-2021-07-01-491</a>","ama":"Sack S, Serbyn M. Quantum annealing initialization of the quantum approximate optimization algorithm. <i>Quantum</i>. 2021;5. doi:<a href=\"https://doi.org/10.22331/Q-2021-07-01-491\">10.22331/Q-2021-07-01-491</a>","short":"S. Sack, M. Serbyn, Quantum 5 (2021).","ieee":"S. Sack and M. Serbyn, “Quantum annealing initialization of the quantum approximate optimization algorithm,” <i>Quantum</i>, vol. 5. Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften, 2021."},"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","month":"07","arxiv":1,"department":[{"_id":"GradSch"},{"_id":"MaSe"}],"file":[{"date_updated":"2021-08-06T06:44:31Z","creator":"cchlebak","date_created":"2021-08-06T06:44:31Z","file_size":2312482,"file_id":"9774","content_type":"application/pdf","access_level":"open_access","file_name":"2021_Quantum_Sack.pdf","checksum":"9706c2bb8e748e9b5b138381995a7f6f","relation":"main_file"}],"article_number":"491"}]